backseat barista
Coffee snobs who drink way too much Starbucks who keep staring at the barista and asking questions while they are making their drink.
Customer: "That's non-fat, right? Make sure it's decaf. I can't have caffeine. You sure that's decaf?"
Barista (in their mind, of course): "if this backseat barista won't shut the hell up, she's getting a little something extra in this latte."
Barista (in their mind, of course): "if this backseat barista won't shut the hell up, she's getting a little something extra in this latte."